Photographic multicolor diffusion transfer process using dye developers and development arrestors



y 1966 w. J. WEYERTS ETAL 3,260,597

PHOTOGRAPHIC MULTICOLOR DIFFUSION TRANSFER PROCESS USING DYE DEVELOPERSAND DEVELOPMENT ARRESTORS Filed Dec. 2. 1960 F su PP 0 RT 20 I RECEPTIONLAYER DEVELOPMENT ARREST OR 2' /ALKA INE QUATERNARYAMMON/UM 22 SALTSILVER HALIDE SOLVENT PRocEssINe COMPOSITION &\\\\ HYDROQUINONEDERIVATIVE LAYER 3 "BLUE-SENSITIVE EMULSION LAYER v-YELLOW DYE DEVELOPERLAYER E/INTERLAYER $70991 /GREEN-SENSITIVE EMULSION LAYER H|| ||||||l||Hllllllllll /MAGENTA DYE DEVELOPER LAYER 7 I l NTER LHYE R-iREDSENSITIVE EMULSION LAYER n CYAN DYE DEVELOPER LAYER 10 SUPPORTYELLOW IMAGE 27 MAGENTA IMAG 26 2! 28 CYAN IMAGE SlageZ INONE DERIVATTVELAYER EMULSION YELLOW DYE DEvELofiER LAYER EMULSION, MAGENTA DYEDEVELOPER LAYER ED-SENSITIVE EMULSION, cYAN DYE DEVELOPER LAYER SUPPORTIilhoMS' IN VEN TORS .ATIURNEYG AGENT fillferlwe eris aflinen/ UnitedStates Patent PHOTOGRAPHIC MULTICOLOR DIFFUION TRANSFER PROCESS USINGDYE DEVEL- OPERS AND DEVELOPMENT ARRESTORS Walter J. Weyerts and WilhoM. Salminen, Rochester, N.Y., assignors to Eastman Kodak Company,Rochester, N.Y., a corporation of New Jersey Filed Dec. 2, 1960, er. No.73,390 9 Claims. (Cl. 963) This application is a continuation-in-part ofour US. patent application Serial No. 51,136, filed August 22, 1960, nowabandoned.

This invention relates to the art of photography and more particularlyto a multicolor diffusion transfer process in photography and materialsadapted to use in the process.

A diffusion transfer color process has been described in a number ofpatents, including British Patent 804,971, published November 26, 1958,wherein photographic elements containing silver halide emulsion layersand layers containing diffusible dye developers (dyes having a silverhalide developing function) are exposed to record the latent image inthe silver halide and then treated with an alkaline processingcomposition which permeates the emulsion layers and layers containingthe dye developers which then develop the latent images to silverimages. At the same time oxidation products of the dye developers areformed in situ with the silver images and which are relativelynon-diffusing in the colloid vehicle of the layers. The non-diffusingcharacter of the oxidized dye developers is apparently due at least inpart to a decrease in solubility in the alkaline processing liquid, andmay also be due to a hardening effect of the oxidized developer upon thecolloid vehicles of the layers which retards the diffusion of theoxidized dye developers. The residual unoxidized dye developersremaining in the layers in imagewise distribution are transferred bydiffusion to a superposed reception element substantially to theexclusion of the silver image and oxidized dye developer to provide apositive dye image.

When an element containing differentially sensitized silver halideemulsion layers is used and subtractively colored dye developers arepresent in or contiguous to the respective emulsion layers, upontreatment with the processing liquid the dye developers are oxidized andrendered non-diffusing in the developed regions of the layers and theresidual dye developer images in the positive regions are transferred bydiffusion and in register to the reception element to provide amulticolor reproduction.

As is apparent, the success of the process depends in part upon theextent to which the dye developers in the exposed (negative) regions ofthe emulsion layers have been rendered substantially non-diffusing inthe development reaction. Thus, if a quantity of unoxidized dyedeveloper remains in a fully exposed negative region corresponding tothe highlights of the subject, it will be transferred to the receptionlayer along with the unreacted dye developer in the positive regions andappears as high minimum density on the resultant color print. Typicaldye developers such as 1,4-bis[p-(2,5-dihydroxyphenyl) ethylamino]-anthraquinone 3,Z9,597 Patented July 12, 1966 o nuomom H OH 0 NHCHaCH Ion are relatively weak silver halide developing agents even when used atthe comparatively high pH of the order of 13 required in the process anddo not so rapidly develop silver halide emulsion as to take fulladvantage of known sensitometric properties of the emulsions and toobtain dye images having a full scale of density and contrast expectedwith other developing agents. As a result, color prints obtained in theprocesses may exhibit an undesirable high minimum density in thehighlight regions, low color saturation, contrast and density and thecolor separation is poor. These effects are due in part to theinefficiency of the dye developers as silver halide developing agents,the lack of discrimination of the dye developers for the silver halidethey should develop and other factors.

The above British patent, and other patents such as referred tohereinafter, relate to various features of the basic diffusion transfercolor process using the dye developers, disclose how to carry outmonochrome processes using the dye developers and that the monochromeprinciples of the particular invention are applicable to the multicolorreproduction. It has been discovered that when sensitive elementsadapted to multicolor reproduction and containing a plurality ofdifferently sensitized silver halide emulsion layers and contiguous dyedevelopers for subtractive color reproduction are used in the process,the problems of the multicolor process and solutions thereof, are muchdififerent from those of the monochrome process. For example, thedevelopment products of one emulsion tend to effect the development ofthe other emulsions, the diffusion of a dye developer from a lower layercan be affected i.e. be hindered, by a dye developer or other substancein an upper layer, the exhaustion of the processing solution by an outerlayer may aifect development of a lower layer and one layer may notdevelop to the extent of another layer, and particularly one dyedeveloper may not be immobilized sufficiently to prevent it fromtransferring and causing color contamination of a dye image of anothercolor. Also, a given dye developer may develop some grains of silverhalide in the wrong emulsion layer with the result than an insuflicientamount of that dye developer is available for transfer and thecorresponding colors are unsaturated thus a magneta dye developer maydevelop some grains of red sensitive silver halide and becomeimmobilized thus decreasing the magenta available to produce red colorswhich then appear unsaturated.

The above-mentioned losses in maximum density of the dye developerimages may result from other causes. As

in other photographic processes, in the development of silver halideemulsions it is desirable to develop substantially only the exposedregions of the emulsions, however, unless precautions are takendevelopment also proceeds to a certain extent in the unexposed regionsresulting in the production of development fog. Compounds known asantifoggants are commonly used to suppress this fog, these compoundsbeing used in the emulsions, developing solutions or both. In the abovedirect positive color transfer process using the dye developers, theformation of development fog in the unexposed regisions results in dyedevelopers being immobilized which should not be, therefore, less dyedeveloper is available for transfer to the receiving layer and theresulting images are lacking in density.

We have investigated the effect of using common antifoggants such asbenzotriazole and 6-nitrobenzimidazole in the alkaline processingsolution in order to prevent these losses in density due to theformation of fog. However, substantial overall fog accompanied by lossof density in the dye developer images is still obtained.

We have now discovered that if the development of the emulsions isarrested, not just suppressed, by means of development arrestors, at thetime when development of the negative is substantially complete, the dyedeveloper images have greatly increased maximum density. The latentimages are thus allowed to develop very rapidly and the developmentarresting effect is delayed until the development of the exposed areashas essentially reached completion before development is appreciablyarrested. This results in the prevention of development of the unexposedareas and the prevention of further development of the exposed areas.The development arrestors such as l-phenyl-5-mercaptotetrazole shouldnot be confused with conventional development antifoggants such as 6-nitrobenzimidazole which retard the reduction of unexposed silver halidebut allow the development of exposed silver halide to proceed. Thedevelopment arrestors stop development of both exposed and unexposedsilver halide and are most effective when an antifoggant is also presentin the alkaline processing solution. This complete arrestment ofdevelopment, particularly in the unexposed areas, results in a greateramount of dye developer being made available for transfer of thereceiving layer, therefore, the greater overall maximum density isobtained in the prints. This complete arrestment of development isparticularly important because the unexposed silver halide is easilyreduced under the strongly alkaline conditions of the processingsolution and this causes the dye developers in these unexposed regionsto be made immobile and thus not available for transfer to the receivinglayer. The development arrestors cannot be used in the alkalineprocessing solution in any appreciable amount or development will bestopped particularly in the outer blue and green sensitive emulsionlayers. When the development arrestors are in the receiving layer andcertain hydroquinone derivatives (below) are also present either in alayer of the sensitive element, in the solution or in a receiving layer,maximum density is increased and color contamination and minimum densityare reduced. Furthermore, when the onium compounds (below) are usedparticularly together with the hydroquinone derivatives even furtherreductions in color contamination and minimum density and furtherincreases in maximum density are obtained. Also, color drop-offdecreases.

Color contamination usually appears in the prints as a degradation ofone or more colors by one or more other colors and may be due to thefailure of one or more dye developers to be immobilized sufficiently toprevent them from transferring from regions where they should have beenimmobilzed. Drop-off appears as a degradation in color quality of theprints apparently caused by one dye developer developing silver halidegrains in the wrong emulsion layer, eg the magenta dye developerdeveloping some red sensitive silver halide grains with the result thatmore magenta dye developer is immobilized than should be and the redcolors are thus deficient in magenta and thus less saturated. Thementioned co-action between the development arrestors, antifog-gants,the onium compounds and the hydroquinone derivatives is particularlyevident when the organic colloid vehicle of the sensitive elementcontaining the dye developers, is composed principally of gelatin. Manyof the common optical sensitizing dyes are conjugated quaternaryammonium salts but they are ordinarily not useful in place of thecolorless onium compounds particularly because they are not sufliciently soluble and diifusible and they impart undesirable stain to theprints.

One object of the invention is to provide photographic elementscomprising several superposed differentially sensitized silver halideemulsion layers having contiguous dye developers and preferablyhydroquinone derivatives, and to provide means for processing theelements including alkaline solutions, preferably containingantifoggants, for initiating development, and reception layerscontaining development arrestors, the onium compounds preferably beingpresent. Sensitive elements, processing compositions and receptionelements particularly adapted to the taking of pictures in a camera andthe processing thereof in a camera will be provided.

The objects of the invention are accomplished in part by descriptionhereinafter of representative sensitive elements comprising a pluralityof silver halide emulsion layers differentially light-sensitive(sensitive to different regions of the spectrum), having contiguous dyedevelopers which may be subtractively colored with respect to thesensitivity of the corresponding emulsion layer, and contiguoushydroquinone derivatives (preferably in a layer of the element), and byprocessing the exposed element by wetting with alkaline processingsolution preferably containing an antifoggant in contact with thereception layer containing the development arrestor, preferably incontiguity with an onium compound diffusible in alkaline solutionthrough the layers such as ternary sulfonium, quaternary phosphonium andespecially quaternary ammonium compounds, to develop the exposed silverhalide in the emulsion layers and thereby render the dye developersthereof non-diffusing in the regions of development, and the developmentarrestor to diffuse to the emulsion layers and stop further development,and allowing the dye developers in the undeveloped regions to transferimagewise by diffusion and in register to the reception layer to yield amulticolor dye developer image thereon having increased density anddecreased color contamination, color drop-01f and minimum density.

In the accompanying drawings are shown in greatly enlargedcross-sectional view the appearance of representative elements employedin a typical process of the invention.

In FIG. 1 of the drawings is shown in flow-sheet form a typical processembodying our invention according to which in stage 1 the sensitiveelement comprises a support 10, layers 11, 12 and 13 containingsubtractively colored alkali-soluble cyan, magenta and yellow dyedevelopers, the light-sensitive halide emulsion layers 14, 15 and 16sensitive to red, green and blue light respectively, the interlayers 17and 18 separating the green-sensitive emulsion and its contiguoussubtractively colored magenta dye developer layer from the other layersand the overcoating layer 19 containing one of the hydroquinonecompounds of the invention. The reception element containing support 20and reception layer 21 containing a development arrestor (which maycontain the onium salt) is positioned so as to receive dye imagestransferring by diffusion from the sensitive element, with a rupturablecontainer of alkaline quaternary ammonium salt-silver halide solventprocessing solution 22 which preferably contains an antifogganttherebetween. Upon rupture of the container 22 as by means of passingthe. assembly between rollers in a camera so as to distribute hecontents uniformly across a predetermined area of the sensitive element,the solution penetrates layer 19 dissolving the substantiallywater-insoluble alkali-soluble and dilfusible hydroquinone derivativeand transporting it to the underlying layers Where the latent images inthe silver halide of areas 23, 24 and 25 are developed to silver and thedye developers in the areas contiguous to areas 23, 24 and 25 eachbecome immobilized and rendered non-difiusing. Thereafter, the unreacteddye developers of layers 11, 12 and 13 diffuse imagewise in register tothe reception layer 21 and form the dye images thereon. The method ofpreparation of the described sensitive element and its use in theprocesses of the invention is described hereinafter.

In FIG. 2 of the drawings is shown an element in which the dyedevelopers are incorporated into the differentially sensitized emulsionlayers 31, 32 and 33, and the hydroquinone derivative is present in thelayer 34 outermost from the support.

In FIG. 3 of the drawings is shown in schematic form, a light-imperviousenclosure useful for processing an exposed roll of film containingsilver halide emulsions and dye developers so as to wet the film withalkaline activator solution and bring it into contact with a mordantedreception sheet for transfer of a series of multicolor dye developerimages to the sheet.

The development arrestors with which our invention is concerned are tobe understood as including those compounds which are capable ofdiffusing in alkaline solution from a receiving 'layer to a contiguoussilver halide emulsion layer undergoing development and thereby stoppingdevelopment of exposed and unexposed silver halide, as opposed toantifoggants capable of only restraining development of silver halideemulsions.

The compounds which are effective as the development arrestors areeither mercaptoazoles diffusible in alkaline solution and azoles whichhydrolyze in alkaline solution to yield mercaptoazoles diffusible inalkaline solution; or iodides diffusible in alkaline solution andcompounds releasing in alkaline solution iodides dilfusible in alkalinesolution. The compounds increase the maximum density of the color printsWithout substantially increasing minimum density.

The following are illustrative of the azole compounds:

S-myristoylthio-l-phenyl-1,2,3,4-tetrazole H N C- S 0 H20 H 0 C H:hydrolyzes to mercaptan) i C a O 55-,8-acetylethylthio-l-phenyl-1,2,3,4-tetrazole2-mercapto-5-phenyl-1,3,4-oxadiazole 2-mercaptonaphth( 1,2) oxazoleZ-mercaptobenzoxazole C-SH Z-mercaptobenzothiazole CSCH2C (C O 0 CH5):(hydrolyzes to mercaptan) 2- (2-dicarbethoxy )ethylmercaptobenzoxazoleThe iodide-containing or iodide-releasing compounds are illustrated bythe following:

Potassium iodide.

(iodide-releasing) III-C Ha Benzothiazolium methiodide.

.HI Hgn (iodide-releasing) NH2 \N/ a bis-(Z-amino-S-iodopyridinehydroiodide)mercuric iodide.

It has been mentioned that the development arrestors are particularlyeffective when an onium compound is present with the result thatincreased density and decreased minimum density, color contamination anddropoff are obtained.

It is believed that the onium compounds interact with the dye developersto form salts thereof and that the improvements, particularly in densityand highlights, are at least due in part to the effect of such saltformation on the solubility and diffusibility of the dye developers.There is evidence that the onium compounds actually temporarily delaythe migration of the dye developers so that the initial difiusion ratesof the dye developers are reduced, yet more of the dye developerstransfer from less exposed areas to increase the density.

Onium compounds haae been used in the photographic art for quite sometime. For example, U.S. Patent No. 2,648,604 discloses the use ofnon-surface-active quaternary ammonium compounds as developmentaccelerators and US. Patents Nos. 2,271,623, 2,271,622 and 2,275,727disclose the use of quaternary ammonium, quaternary phosphonium andtertiary sulfonium compounds as sensitizers for silver halide emulsions.Notwithstanding the fact that such onium compounds have been previouslyused as sensitizers and as development accelerators, the mentionedresults obtained by using onium compounds in conjunction with the dyedevelopers in the diffusiontransfer processes of this invention areworthy of note. In the processes disclosed in the above-mentioned US.patents, there is an increase in silver density in the negative due tothe use of the onium compounds; however, the increase in density in suchprocesses takes place in the exposed areas of the negative and isattributable to the above-mentioned ability of the onium compounds tosensitize an emulsion or to accelerate development. In the presentprocesses, when an increase in density is obtained it takes place in thepositive image and is primarily the result of increased transfer of thedye developer from unexposed areas of the negative. The fact that theonium compounds would coact with dye developers to increase the transferof such dye developers from unexposed areas of the negative in no waywas expected from the prior use made of such compounds as sensitizers ordevelopment accelerators. Further, the improvements in the presentprocesses are not necessarily the result of improved surface activitydue to the onium compounds because the onium compounds which usuallybring about the greatest improvement in density would not be generallyclassified as surface active. It is believed that the increase indensity is at least due in part to the ability of the onium compounds toincrease the solubility of the dye developers.

The fact that the onium compounds would also act, especially in thepresence of the hydroquinone derivatives, to inhibit transfer of theoxidized dye developers from the exposed areas and thus improve thehighlights, -was similarly unexpected. This improvement in highlights isbelieved to be due to the ability of the onium compounds to control,especially in the exposed areas, the dilfusibility of such dyedevelopers.

Especially useful results have been obtained through the use ofquaternary ammonium compounds. As is known, quaternary ammoniumcompounds are organic compounds containing a pentavalent nitrogen atom.Generally, they can be considered as derivatives of ammonium compoundswherein the four valences usually occupied by the hydrogen atoms areoccupied by organic radicals. Generally, the organic radicals are joineddirectly to .the pentava'lent nitrogen through a single or doublecarbon-to-nitrogen bond. The term quaternary ammonium, as used herein,.is intended to cover compounds wherein the pentavalent nitrogen is oneof the nuclear atoms in a heterocyclic ring as well as those whereineach of the four valences is attached to separate organic radicals,e.g., tetraalkyl quaternary ammonium compounds. As illustrations ofquaternary ammonium compounds, mention may be made of those representedby the following formulae:

wherein each R is an organic radical, Y is an anion, e.g., hydroxy,bromide, chloride, toluene sulfonate, etc., and Z represents the atomsnecessary to complete a heterocyclic ring. As examples of compoundswithin Formulae 1, 2 and 3, mention may be made of tetraethylammoniumbromide, N-ethylpyridinium bromide, N,N-diethylpiperdiniu bromide,ethylene-bis-pyridinium bromide, l-ethylpyridinium bromide,1-phenethyl-3-picolinium bromide, tetra-alkylammonium salts,cetyltrimethylammonium bromide, polyalkylene oxide bis-quaternaryammonium salts such as polyethylene oxide bis-pyridinium perchlorate,the heterocyclic quaternary ammonium salts mentioned which form themethylene bases including 3-methyl-2- ethylisoquinolinium bromide, 3methylisoquinolinium methyl p toluenesulfonate, 1 ethyl 2 methyl 3-phenethylbenzimidazolium bromide, 5,6-dichloro-l-ethyl-2-methyl-3-(3-sulfobutyl)-benzimidazolium betaine and the pyridiniumsalts below.

The tertiary sulfonium and quaternary phosphonium compounds may berepresented by the formulae:

wherein each R is an organic radical, e.g., alkyl, aralkyl, aryl, etc.groups, and X is an anion, e.g., hydroxy, bromide, chloride, toluenesulfonate, etc. As examples of tertiary sulfonium and quaternaryphosphonium compounds, mention may be made of lauryldimethyl-sulfoniump-toluene-sulfonate, nonyl-dimethyl sulfonium ptoluene sulfonate andoctyldimethylsulfonium p-toluene sulfonate, butyldimethylsulfoniumbromide, triethylsulfonium bromide, tetraethylphosphonium bromide,dimethylsulfonium p-toluene sulfonate, dodecyldimethylsulfoniump-toluene sulfonate, decyldimethylsulfonium p-toluene sulfonate andethylene-bis-oxymethyltriethylphosphonium bromide.

The onium compounds may be used as the hydroxide or as the salt. Whenthe onium compounds are used as the salt, the anion may be a derivativeof any acid. However, it should be noted that when the anion is iodide,such iodide may have deleterious efiects on the emulsion and suitableprecautions should be taken. Especially good results were obtained whenthe onium compounds were employed as the bromide.

The particularly efiicacious heterocyclic quaternary ammonium compoundswhich form the methylene bases dilfusible in alkaline solution have thegeneral formula wherein D represents the non-metallic atoms necessary tocomplete the heterocyclic nucleus of the quaternary ammonium compoundcontaining 1 or more of the reactive methyl groups -CI-I R' in one ormore of the nuclear positions, the other nuclear positions beingsubstituted or not, such as quaternary salts of the pyridine, quinoline,benzoquinoline, benzoxazole, benzoselenazole, thn'azole, benzothiazole,naphthothiazole, benzimidazole, isoquinoline series, etc., n is 0 or 1,R is an alkyl group, an aryl or aralkyl group of the benzene series, orsubstituted alkyl, aryl or aralkyl groups of the benzene series, thealkyl chains preferably being lower alkyl of from 1 to 4 carbon atoms,R' is a hydrogen atom or one of the groups represented by R, and Xrepresents OH- or an acid anion such as Br, CH SO or One or more ofthese quaternary ammonium compounds can be used alone or in combinationwith the onium compounds having the Formulae 1, 2, 3, 4 and 5 above, andare advantageously employed in either the processing solution, thereception element, or both, and less desirably in the light-sensitiveelement per se, to improve the print quality by a mechanism not fullyunderstood. When the hydroquinone derivatives are also present aco-action with the quaternary compound takes place such that a greatlyimproved efl'ect is obtained distinguishable from the effect of eitherthe hydroquinone derivative or the quaternary compound. The dye printsobtained exhibit appreciably less color contamination and improved colorsaturation, density and contrast.

The onium compounds can be used in varying amounts depending upon theparticular compound and two or more can be used in combination. Whenused in the alkaline processing solution, useful results can be obtainedwith from about 0.2 to 15% of onium compound. In some cases about 0.2 to3% is best. Similarly, the amount used in the sensitive element andreceiving sheet will vary with the onium compound selected.

The quaternary ammonium compounds comprising a preferred embodiment ofthe invention are pyridinium salts which form the ditfusible methylenebases and which have the above Formula 6, the pyridinium nucleus beingsubstituted with from 1 to 3 active methyl groups CH R' present in atleast one of the 2, 4 or 6 positions, e.g. a

7 lower alkyl group such as methyl, ethyl, propylor substituted loweralkyl groups such as hydroxyalkyl, e.g. hydroxyethyl, which alkyl groupsact as methylene base precursors. Positions 3 and may or may not besubstituted with e.g. halogen, lower alkyl and haloalkyl groups such aschlorine, methyl, ethyl, propyl or chloroethyl groups.

Typical salts having the above Formula 6 are as follows:

l-benzyl-Z-picolinium bromide Br- CH3. Ni

I CsHaN pts Br Anhydro-1-(4-sulfobutyl) -2-picolinium hydroxide i CH2drmsoh OH- a-picoline-fi-naphthoylmethylbromide i OHa-1-18-phenylcarbamoyloxyethyl-Z-picolinium bromide (i12H4OCONHCoH1-methyl-2-picolinium pts 1-phenethyl-2,4,6-trimethylpyridinium bromidel-phenethyl 4-n-propylpyridinium bromide 4-y-hydroxypropyl-l-phenethylpyridinium bromide, andl-n-heptyl-Z-picolinium bromide A number of pyridinium salts having theabove general formula do not form methylene bases sutficientlydiffusible in alkaline solution to be of practical use in the processe.g.

1-n-decyl-2-picolinium bromide 1,2-dibenzyl pyridinium bromide6-amino-l-phenethyl-Z-picolinium bromideZ-amino-l-phenethyl-4-picolinium bromide Z-benzyl-l-phenethyl pyridiniumbromide 4-benZy1-1phenethy1 pyridinium bromide The following which donot form methylene bases in alkali solutions are also less useful.

1Q l-phenethyl pyridinium bromide l-ethyl pyridinium bromidel-phenethyl-3-picolinium bromide l-n-nonylpyridinium pts Thehydroquinones which have the requisite properties are substantiallycolorless, substantially water-insoluble, and soluble and difiusible inalkaline solution through organic colloid layers such as gelatin and areexemplified by the following Phenylhydro quinone2-hydroxyphenylhydroquinone Phenoxyhydroquinone4-methylphenylhydroquinone 1,4-dihydroxynaphthalene 2-(4-aminophenethyl) -5-bromohydroquinone 2- (4-aminophenethyl)-5-methylhydroquinone 4'-aminophenethylhydroquinone2,S-dimethoxyhydroquinone 2,5-dibutoxyhydroquinone m-XylohydroquinoneBromohydroquinone 3,6-dichlorohydroquinone2-dimethylaminomethyltoluhydroquinone 2-cyclohexylhydroquinone Sec.'butylhydroquinone 2,5-dichloro-hydroquinone 2,5-diisopropylhydroquinone2,5-diiodohydroquinone 3-chlorotoluhydroquinone Tetrachlorohydroquinone2,5-diphenylhydroquinone 2,5 -diresorcylhydroquinone2,5-dioctylhydroquinone Dodecylhydroquinone The useful hydroquinonederivatives are particularly distinguished from the dye developerscontaining hydroquinonyl moieties mentioned hereinafter, in beingsubstantially colorless and therefore do not impart any color to theprint.

The processes of the invention are thus preferably carried out with thesilver halide emulsions and dye developers in contiguity with the oniumcompounds and the hydroquinone derivatives a development arrestor beingin the reception layer and an antifoggant preferably in the alkalinesolution. The onium compound may be present in either or both thealkaline processing solution, in the reception sheet, less desirably inthe sensitive element, and the hydroquinone derivative in any of thelayers of sensitive element such as an overcoating layer, emulsionlayer, dye developer layer, an interlayer or in a reception layer. Forsome purposes the hydroquinone derivatives may be present in theprocessing fluid; however, in the present invention this is lessdesirable since the hydroquinone derivatives are unstable in suchsolutions and readily undergo oxidation accompanied by discolorationofthe prints.

The hydroquinone derivatives used as described, are preferablyincorporated into emulsion layers, overcoating interlayers or otherlayers, as dispersions in the hydrophilic organic colloid vehicle of thelayer. The hydroquinone derivatives may be dissolved in alkalinesolution and precipitated into aqueous gelatin solutions by raising theacidity of the solution. However, this is a less desirable procedurebecause of the instability of the compounds in alkaline solution. Thehydroquinone derivatives may be dissolved in a solvent, such as a loweralcohol, and precipitated into aqueous gelatin solutions for coating onthe sensitive element. They may be added to gelatin solutions which areball-milled to reduce the crystal size. However, the hydroquinones arepreferably dissolved in a low molecular weight water-insoluble organiccrystalloidal solvent permeable to the alkaline processing solutions andhaving a boiling point above about C. such as dibutyl phthalate andadded to an aqueous gelatin solution which is passed through a colloidmil-l until the desired degree of subdivision has been attained. Anauxiliary organic solvent can also be used such as one having asolubility in water greater than that of the crystalloidal solvent, ofthe order of at least about 2 parts per 100 parts of water. Thus theauxiliary organic solvent can be Washed from a chilled gelatindispersion in the presence of the other solvent. The auxiliary solventmay be one having a boiling point at least about 25 C. lower than thecrystalloidal solvent in order that it can be removed by volatilizationduring the drying of a coating to leave the hydroquinone derivativedispersed in only the crystalloidal solvent. As a result, thehydroquinone derivatives are quickly and uniformly dissolved by thealkaline processing composition and transported throughout the sensitiveelement to produce more uniform development than when the hydroquinonederivatives are incorporated into the element by other means.

The hydroquinone derivatives may be used in one or more layers of thesensitive element in quantities of the order of from about to 100 mgs.or more per square foot. However, the quantity used depends in part uponthe amount of silver halide, the layer in which it is contained, theamount of dye developer and the amount of pyridinium salt in thesensitive element or processing solution of reception element. In someinstances it may be desirable to form a complex of the hydroquinonederivatives by reaction with sulfur dioxide in a wellknown manner and toincorporate the complex in the overcoating layer, outer emulsion orother layer of th sensitive element. These complexes tend to be moistable than the hydroquinone derivatives themselves.

The dye developers which are used in the emulsion layers or in layersadjacent to the emulsion layers are compounds which are both a silverhalide developing agent and a dye. They are characterized by beingrelatively non-diffusible in the colloid layers at a neutral pH butditfusible in the layers in the presence of the alkaline processingsolutions. For the most part the dye developers are insoluble in waterper se, which property usually necessitates the use of organic solventsto incorporate the dye developers into the organic colloid layers of thesensitive elements. Otherwise, the solubility of the dye developers isnot particularly important and so long as the dye developers are capableof being immobilized in the layers in the presence of the alkalineprocessing solution and they are transferrable to the reception element,they are useful in the process of the inven tion. The dye developers areparticularly characterized by containing both a chromophore moiety andat least one moiety such as a hydroquinonyl radical having a silverhalide developing agent function and which radical imparts silver halidedevelopment activity to the dye developer molecule as a whole with theresult that during development of a silver halide image, the dyedevelopers are oxidized to less difiusible compounds in the region ofexposure and development and the residual dye developers in theundeveloped regions are transported imagewise to mordanted receptionlayers to provide a dye image thereon. The dye developers of courseshould not have a desensitizing action toward silver halide emulsions.

Representative dye developers of use in the sensitive elements of theinvention have the general formula in which M is an aromatic orheterocyclic ring or ring system such as a benzene, naphthalene,tetralin, anthracene, anthraquinone, pyraz'ole, qu-inoliue, etc., ringand may also be substituted, as by hydroxyl amino, keto, nitro, alkoxy,aryloxy, acyl, alkylamido, arylamido, alkyl, aryl, carboxamido,sulfonamido, carboxyl or sul-fo groups. D represents a silver halidedeveloping agent moiety imparting the developing agent function to thedye developer such as a hydroquinolyl group which may be substitutedwith amino, alkylamino, alkyl, hydroxyl, alkoxyl or halogen groups.

A very useful type of dye developers disclosed in Australian Patent220,279 accepted December 17, 1958 and German Patent 1,036,640, August14, 1958 have the general formula open chain reaction methylene couplercontaining the group -CO-CH CO--, for example:

4- [p-( 2',5 -dihydroxyphenyl) -phenylazo] -5-acetamido- 1-n aphthol.

4- [p-( 2',5 -dihydroxyphenethyl) -phenylazo] -5-benzamido- 1 -naphthol.

1-phenyl-3 -methyl-4- [p-(2',5 '-dihydroxyphenethyl) phenylazo]-5-pyrazolone.

2- [p- 2, -dihydroxyphenethyl) -phenylazo] -4- acetamidol-naphthol.

2- [p- 2, 5 dihydroxyphenethyl) -phenylazo] -4- aminol-naphthol.

(|)H O H CHa-OH2N=N (magenta dye developer) I O H O C H3 2- [p- (2',5'-dihydroxyphenethyl) -phenylazo] -4- methoxy-l-naphthol.

2- [p- (2',5 'dihydroxyphenethyl -phenylazo] -4- ethoxyd-naphthol.

2- [p- (2', '-dihydroxyphenethy1) -phenylazo] -4- n-propoxyl-naphthol(Compound 11) l-phenyl-3-N-n-butyl-carboxamido-4-[p-2',5-dihydroxyphenethyl) -phenylazo] -5 -pyrazolone.

1-phenyl-3-N-n-hexylcarb ox amido-4- p-'( 2',5 '-dihydroxyphenethyl)phenylazo] -5-pyrazolone (Compound IH) l 1-phenyl-3-carbethoxy-4-[p-=(2,5 '-dihydroxyphenethyl) phenylazo] -5-pyrazolone.

2- [p 2',5 -dihydroxyphenethyl) phenylazo] -4-isopropoxyl -naphthol.

1-phenyl-3-N-cyclohexyloarb ox amido-4- [p- 2',5 '-dihydroxyphenethyl)phenylazo] -5-pyrazolone.

1-phenyl-3-phenyl-4- [p-( 2',5 -dihydroxyphenethyl) phenylazo] -5-pyrazolone.

2-(4- [p- (2",5 "-dihydroxyphenethyl) -phenylazo]-0tnaphthylazo-4-methoxy)-1-naphtho1.

1-phenyl-3-amino-4- (4'- [p-(2,5-dihydroxyphenethyl) -phenylazo] -2',5'-diethoxyphenylazo pyrazolone.

1-acetoxy-2- [p-(B-hydroquinonylethyl) -phenylazo] -4- methoxynaphthalene.

4-isobutoxy-2- [p- (B-hydroquinonylethyl) -phenylazo] l-naphthcl.

l-acetoxy-Z- [p-(ti-hydroquinonylethyl) -phenylazo] -4- propoxynaphthalene.

2- [p- 2',5 -dihydroxy-4'-methylphenethyl) phenylazo] 4-propoxyl-naphthol.

1-phenyl-3- [N-( B-ethylhexyl) -carboxamido] -4-[p-(fl-hydroquinonylethyl) -phenylazo] -5-pyrazolone.

1-phenyl-3( N-n-heptyl) carboxamido-4-[p- (ti-hydroquinonylethyl)-phenylazo] -5-pyrazolone.

l- (o-carboxyphenyl -3-phenyl-4- [p-(2,5-trifluoroacetoxy-fl-phenylethyl) phenylazo] -5-hydroxy pyrazole lactone.

lo-carboxyphenyl) -3-N-phenylcarb oxarnido-4- [p-(BC hydroquinonylethyl)-phenylazo] -5-hydroxy pyrazole lactone.

I Another class of dye developers disclosed by British Patent 804,971,November 26, 1958, and British Patent 804,973, November 26, 1958 havethe general formula group, which may be aliphatic, e.g., acetyl oraromatic, 'e.g. benzoyl, Z is a bivalent organic radical containing atleast one methylene (CH group, m is a positive integer less than 5 andeach Y may be a hydrogen or halogen atom or an amino, alkyl, aryl,nitro, alkylamino, arylamino, aryloxy, alkoxy, hydroxyl, sulphonamido,

carboxamido, carboxy, sulpho,

' Examples of these dye developers are 1,4-bis-( 2',5'-dihydroxyani1ino-anthraquinone, 1,5 -bis(2,5 -dih'ydroxyanilino-4,8-dihydroxyanth'raquinone,

1,4-bis ,8-( 3 ',4'-dihydroxyphenyl ethylamino] anthraquinone,

OH CH3 I I O lfHCH-CHzl l I (cyan dye developer) 0 H NH? H-CH CH:

1,4-bis [,B- (2',5-dihydroxyphenyl) -isopropylamino] anthraquinone,

. 1,4-bis ,8- (2',5 '-dihydroxyphenyl -ethylamino] anthraquinone,

1-chloro-4-[B-(2',5'-dihydroxyphenyl)ethylamino] anthraquinone,N-monobenzoyl-lA-bis-[fi-(3',4'-dihydroxyphenyl) ethylamino]-anthraquinone, N-monobenzoyl-l,4-bis[B-(2',5'-dihydroxyphenyl)-ethylamino] -anthraquinone,5,8-dihydroxy-1,4-bis[(p-hydroquinonyl-a-methyl)ethylamino]-anthraquinone (Compound I) 1,4-bis 8-hydroquinonyl-a-ethyl)ethylamino] anthraquinone,

5 -hydroxy-1 ,4-bis fi-hydroquinonyl-a-methyl) ethylamino]-anthraquinone,

1- B-hydroxy-w-ethyl-ethyl amino -4- a-hydroquinonyla-methylethyl-amino-anthraquinone and1-(butanol-2'-amino)-5,8-dihydroxy-4-hydroquinonylisopropyl-amino-anthraquinone.

In the formulas above the expression bivalent organic radical Z refersto organic radicals having the two free valences attached to differentatoms. As examples of such suitable bivalent organic radicals, mentionmay be made of alkylene radicals such as (I311: -CHg, -C H2-CHz, O HZ CHas well as bivalent radicals such as It is also intended that Z may besaturated, unsaturated, such as CH CH=CH-CH or substituted, such aschloroalkylene or hydroxyalkylene.

Where Z is an alkylene group, best results are obtained by the use of alower alkylene group, e.g. an alkylene group, containing less than aboutsix carbons, and preferably an ethylene (CH CH group. Alkylene groupscontaining more carbon atoms may be used, however, providing that theresulting dye developer is capable of being dissolved in the liquidprocessing composition described herein, and its oxidation productrendered im mobile in the developed emulsion layer.

Acylation of amino-nitrogen atoms which are part of the chro-mophoricsystem has the effect of shifting the visible absorption band of thecompound toward higher frequencies (shorter wave-lengths). Thus,acylating one amino-nitrogen of the cyan,1,4-bis-[[3-(2',5'-dihydroxyphenyl)ethylamino]-anthraquinone changes itscolor to a magenta, and acylating both the amino-nitrogen atoms changesits color to an orange-yellow. Similarly the acylation of hydroxylgroups of the above types of dye developers can be expected to shift thecolor of the dye developers. Thus, the dye developers may undergo achange in structure and/or color during the development reaction, forexample through hydrolysis, and the dye which is transferred may have acolor different than that of the dye developer originally present in thesensitive element.

Additional dye developers are disclosed in Belgium Patent 554,935,British Patents 804,971, 804,973-5 and French Patent No. 1,168,292.

The following dye developers are also useful in the sensitive elementsand processes of the invention:

Cyanurated dye developers such as 2-hydroquinoneamino-4-(p-phenylazo)anilino-6-hydroxy-4-triazine (Canadian Patent No. 579,038).

Anthraquinone dye developers such as 1,4-bis(2',5'-dihydroxyanilino)-a11thraquinone and 1,4-diamino-N- (/3- 2,5dihydroxyphenyl-a-methyl-ethyl) -2,3 -anthraquinonedicarboximide.

Amino substituted tanthraquinoue dye developers such as prepared byreaction of 1-amino-4-(p-aminoanilino)- anthraquinone-Z-sodium sulfonatewith chloroacetamido hydroquinone mon'obenzoate.

Dye developers obtained by reaction of 1-phenyl-3-amino-4-phenylazo-5-pyrazolone or 1,4-bis-(18-aminoethylamino) -anthraquinone with h'omogentisic acid lactone or acid chloride, or gentisicacid chloride e.g. 1-phenyl-3-(2',

'-dihydroxyphenyl-acetamido -4-phenylazo-5-pyr azolone' (Blout et a1.Canadian Patent 577,021 dated June 2, 1959).

Naphthamide dye developer such as 1-(2,5-dimethoxyphenyl-azo 2-hydroxy N(2',5'-dihydroxypheny-l)-3- naghthamide (French Patent 1,168,292 datedAugust 25, 19 8).

Disazo dye developers such as 2-[p-(1-hydroxy-3,6-disulfo-8-amino-2-naphthylazo)-3,3'-dimethoxybisphenyleneazo]-hydroquinoneand 2-(2',5'-dimethoxy-4'[p-(2", 5" dihydroxyphenethyl) phenylazo]phenylazo)-l,8- naphthalene diol-3,6-disulfonic acid.

Arylazonaphthol dye developers, e.g. 1-a-min0-4-phenylazo-2-naphthol.

Anthrapyridone dye developers e.g. l-acetyl-3-fl-(2',5'-dihydroxyphenyl)-ethyl-6-fl-(2',5 dihydroxyphenyl)-ethylaminoanthrapyridone.

Thiohydroquinoyl dye developers, e.g. l-phenyl-3- methyl 4 [p (2',5dihydroxyphenylthioethyl)- phenylazo]-5-pyrazolone (Belgian Patent568,344).

Ortho coupled dye developers exhibiting limited sensitivity to changesof pH e.g. 2-(p-[2",5"-dihydroxyphenoxy]phenylazo)-4-methoxy-1-naphtholand 1-phenyl-3- methyl-4-[p-hydroquinolylsulfonyl)-phenylazo-]S-pyrazolone.

Oxalyl ester dye developers, e.g. 1-phenyl-3-amino-4[p-(2,5'-bis-ethoxalyloxyphenethyl) phenylazo] 5-pyrazolone.

Leuco compounds may be used similarly e.g. l-phenyl- 3-methyl4-(2'-methyl-4'-diethylamino)anilino-S-pyrazolone, which do not exert afiltering action on underlying emulsion layers and which are immobilizedin the developed regions, difiuse imagewise from undeveloped areas tothe reception layer and are oxidized to colored images therein.

The dye developers may be incorporated into the emulsion layers or intothe layers thereunder by several methods. For example, the dyedevelopers may be dissolved in organic solvents and precipitated intogelatin solution or the dye developers may be ball-milled in gelatinsolutions to reduce their particle size. However, particularly favorableresults are obtained when the hydroquinone derivatives of the inventionare present in one or more of the layers of the sensitive element andthe dye developers have been incorporated into the gelatin layers underthe emulsion layers (as shown in FIG. 1) by dissolving the dyedevelopers in high boiling solvents such as ditetrahydrofurfuryl adipateor 2-(2-butoxyethoxy)ethyl acetate and milling the mixture in gelatinsolution in a colloid mill. When high boiling solvents having lowsolvent activity for the dye developers, such as dibutyl phthalate, areused it is desirable to dissolve the dye developer in a mixture of thehigh boiling solvent and a low boiling solvent such as cyclohexanone,methanol, etc., which evaporates readily from the coatings during thesubsequent drying operation. Many of the dye developers can be used withthe high boiling solvents (in absence of low boiling solvents) such asthe following:

Ditetrahydrofurfuryl phthalate B-methoxyethyl phthalate EthylN,N-di-n-butylcarbamate Guaiacol acetate (o-methoxyphenyl acetate)Tetrahydrofurfuryl propionate Triethyl citrate Acetyl triethyl citrateTricresyl phosphate Tri-p-tert.butylphenyl phosphate TriethylphosphateTri-n butylphosphate Triphenylphosphate 1.6 Isoamyl acetateDitetrahydrofurfuryl succinate Methyl acetate Ditetrahydrofurfuryladipate Tetrahydrofurfuryl benzoate N-n-amylphthalimide EthylN,N-di-n-butylcarbamate Diethyl lauramide Dibuytl lauramide Lauroylpiperidine N-n-butyl acetanilide Tetraethyl phthalamide N-n-amylsuccinirnide 4-methyl-2-pentanol 2,4-di-n-amylphenol Ethylene glycolmonobenzyl ether Methyl isobutyl carbinol Furfuryl alcohol Cyclohexanone2-(2-butoxyethoxy)ethyl acetate The isomeric 2-, 3- and4-methylcyclohexanones are particularly useful lower-boiling solventsfor use with the above high-boiling solvents for dispersion of dyedevelopers such as the cyan dye developersl,4-bis-(-2,5-dihydroxyphenylisopropylamino)-anthraquinone, 5,8-bis [B-hydroquinoyl-a-methyl)ethylamino]quinizarin and 1,4-bis(2,5-dihydroxyphenylisopropylamino) 5 hydroxyanthraquinone, and themagenta dye developer 4-meth- 0xy-2-[p-(,B-hydroquinoylethyl)phenylazo]-1-naphthol. As a result the gelatin solutions containingdispersions of dye developers produce stable dried coatings in which thedye developers do not tend to crystallize out.

The dye developers are employed in the sensitive elements contiguous tothe silver halide of the emulsion layers, that is, they may be presentin one or more of the emulsion layers or preferably in a hydrophilicorganic colloid layer immediately next to and particularly under thesilver halide emulsion layer. Especially good results are obtained whenthe dye developers are positioned so as to be present in the layerimmediately under the emulsion layer, the sensitivity of whichiscomplementary to the color of the dye developer as shown in FIG. 1 ofthe drawings. It appears less desirable to locate the dye developer in alayer positioned above the corresponding layer of silver halideemulsion. The contiguity of the dye developer with respect to the silverhalide can take the form of a mixed packet system wherein the dyedeveloper may be present in a matrix surrounding a particle or globulecontaining silver halide grams.

In multilayer sensitive elements of the type shown in FIG. 1 the orderof arrangement of the dilferentially sensitized silver halide emulsionlayers on the support can be diflerent, e.g. reversed so as to have thebluesensitive emulsion layer on the support and. the redsensit-iveemulsion layer outermost. In such arrangements of layers thesensitivities of the silver halide emulsions should be adjusted so as toprevent recording unwanted blue light images in the emulsions primarilysensitive to the red and green regions of' the spectrum, e.g. a silverbromide emulsion can be used for the blue sensitive emulsion and silverchloride emulsions for the other layers. In instances of this type itmay be desirable to utilize the leuco compounds mentioned above in placeof one or more of the dye-developers which, since they may have someblue absorption, might tend to exert an undue filtering action on theblue-sensitive, bottom emulsion layer.

The hydrophilic organic colloid vehicle of the emulsion layers,overcoating layers, of the dye developer layers and of interlayers canbe varied somewhat, for example, gelatin, gelatin derivatives such asdibasic acid esters of gelatin, polyvinyl alcohol and cellulose acetatehydrogen phthalate or mixtures of these may be used. However, the bestand most consistent results, and conshould be at least about 75% of themeasured thickness of the yellow dye developer layer and contain atleast about two times the amount of gelatin present in that layer inorder to prevent undue wandering of the dye development products fromlayer to layer. Other hydrophilic organic colloids yield less desirableresults when used in the layers. For example, when some of the layerscontain gelatin vehicle and 'interlayers of polyvinyl alcohol orcellulose acetate hydrogen phthalate are used, the layers tend to stripapart particularly when dry. Also, when gelatin is used throughout moreuniform transfer of the alkaline processing solution and hydroquinonederivative through the layers is obtained and the dye developerscomprising the final print transfer more readily to the reception layer.

The processing solution used to initiate development of the exposedsensitive elements containing the dye developers and hydroquinonederivatives, and which may contain the quaternary ammonium salt, shouldbe strongly alkaline to accelerate the development activity of the dyedeveloper as much as possible. Alkali metal hydroxides such as sodiumhydroxide or alkaline salts such as sodium carbonate are advantageouslyused in the activator composition for this purpose. However, quaternaryammonium hydroxides or volatile amines such as diethyl amine, which havethe advantage of being volatilized from the prints and therefore leaveno residue of alkali thereon which might tend to decompose the dyeimages, may also be used. As mentioned previously, since thehydroquinone derivatives may tend to be unstable in the stronglyalkaline activator, they are preferably not incorporated in theprocessing solution although when the pyridinium salts are present,results are obtained which are satisfactory in other respects. Theresults most desired are obtained when the hydroquinone derivative ispresent in the layers of the sensitive elements. Therefore, no silverhalide developing agent need be present in the processing solution.

The sensitive elements of the invention are of course adapted to use ina camera for taking pictures in the usual manner. Moreover, thedevelopment of the sensitive elements, i.e. the treatment with analkaline activator solution to initiate development, can also be carriedout in the camera by use of rupturable containers of processing solutionused as illustrated in FIG. 1 of the drawings or other means may be usedto spread the processing solution uniformly across the picture area ofone or more consecutively exposed images and in contact with thereception layer. For this purpose, it may be desirable to use aprocessing solution containing in addition to strong alkali a thickeningagent such as carboxymethyl cellulose or high-viscosity hydroxyethylcellulose in suitable quantity to obtain the desired viscosity. Othermeans can be used such as spraying, dipping, roller coating, etc. toapply to the processing solution to the exposed element and to initiateits development. The alkaline processing solution may be replaced withWater or a water solution of pH 7.5 or less if the contiguous receivingsheet contains an alkali or an alkali releasing material. If the wateror water solution is integumented and incorporated in the lightsensitive element or in the mordanted receiving sheet it may be releasedby suitable mean such as by pressure or by heat.

Thus, several consecutive exposures on a strip of the sensitive elementcan all be wetted with the alkaline processing solution and the dyedeveloper images transferred to a single strip of reception material toprovide several color prints in a single transfer operation.

One method for obtaining the color prints from a strip of the sensitiveelement containing a series of, for example, three or four consecutiveexposures, is to apply a viscous processing solution from a releasablyconfining or rupturable container in a compartment such as a magazine,integral with a camera in the manner described below, to cause each ofthe exposed areas to be wetted with the processing composition atapproximately the same time in cont-act with a strip of receptionmaterial and the corresponding multicolor images to transfer thereto toprovide a series of colored images on a single strip of the receptionmaterial.

A different means for providing prints from the sensitive elementcontaining a series of image exposures such as three or four consecutiveexposures, is to expose the element to several subjects in aconventional camera not necessarily adapted to use of rupturablecontainers of the processing composition, and withdrawing the exposedelement from the camera in a convenient manner so as to prevent foggingof the emulsions. Thus, the element can be exposed and wound upon itselfon a spool in an ordinary roll-film type of camera so as to excludelight, by use of a light-impervious covering such as black paper, acassette or a magazine. The element can then be withdrawn from thecamera and placed in a convenient portable light-impervious enclosure ofsmall dimension such as shown in FIG. 3, for application of theprocessing fluid to the element from, for example, a single rupturablecontainer or several rupturable containers corresponding to the numberof exposures recorded on the strip of sensitive element, or byapplication of the viscous or non-viscous fluid to the element by meansof a Wick, roller or similar applicator, so that each of the exposedareas is wetted. As a result, the element comprising several imageexposures on a single strip of differentially light-sensitive emulsionlayers and subtractively colored dye developers contiguous to the silverhalide of each emulsion layer, is wetted with the alkaline fluid in thepresence of the cationic onium salts, and in the presence of thehydroquinone derivatives, and brought into contact with the receptionlayer for a time sufficient for adequate development of each image, tocause the silver halide in the several exposed areas of each emulsionlayer to develop and thereby render the corresponding dye developersimmobile and the dye developers in the unexposed portions of each of theseveral exposed areas to transfer to the reception layer and provide aseries of prints thereon composed of the dye developers. In FIG. 3 isshown a schematic representation of an apparatus useful for this purposeand the process for making the series of prints from a sensitive elementcontaining a series of exposures. The film 40 wound emulsion sideinwards, having the structure shown in FIG. 1, Stage 1 and comprising asupport having superposed thereon differentially sensitized emulsionsand contiguous dye developers, which has been exposed so as to record aseries of multicolor subjects, is quickly passed between rollers 41 and42 so as to pick up the alkaline activator solution 43, such asActivator II, contained in pan 44, which is supplied by roller 42dipping into the solution. Thence the film continues between rollers 45and 46 where it is brought into contact with the mordanted receivingsheet 47, such as Receiving Sheet A, to form the sandwich 48. Theexposed silver halide in each emulsion layer then develops,corresponding dye developers become immobilized and the unreacted dyedevelopers then transfer to sheet 47, after which the sandwich passesout of the enclosure and is stripped apart to provide a series ofpositive dye developer images on sheet 47 at 50.

Camera apparatus of the type useful for exposing and processing thesensitive elements of the invention have been described, for example, inUS. Patent 2,435,717. Such cameras permit successive exposure ofindividual frames of the photosensitive element from the emulsion sideas Well as processing of an exposed frame by bringing the exposedportion of the photosensitive element in superposed relation with aportion of the print receiving element while drawing these portions ofthe film assembly between a pair of pressure rollers which rupture thecontainer associated therewith and spread the processing liquid betweenand in contact with the photosensitive element and the correspondingregistered area of the print receiving element. The photosensitiveelement and print receiving element during the spreading of thecontainer contents become formed into a combination wherein thephotosensitive element and print receiving element are so superposedwith respect to each other that the spread liquid has access to both ofthe elements. This superposed relationship between the photosensitiveand print receiving elements is maintained until the elements arestripped apart following the deposit on the print receiving element ofthe dye forming the final color image.

The reception layers containing the development arrestors may becomposed of various materials such as linear polyamides, proteins suchas gleatin, polyvinyl pyrrolidones, poly-4-vinyl pyridine, polyvinylacetate, polyvinyl alcohol, cellulose acetate, polyvinyl salicylal,partially hydrolyzed polyvinyl acetate, methyl cellulose, regeneratedcellulose, carboxym'ethyl cellulose and hydroxyethyl cellulose, andmixtures thereof.

As will be apparent from a consideration of other color processes usingdyes, the prints composed of the dye developers undergo decomposition tosome extent when exposed to heat, light and moisture. Accordingly, it isadvantageous to treat the prints to reduce these effects as much aspossible. For this purpose solutions of a number of materials can beswabbed on, sprayed on or otherwise applied to the prints to improve thestability of the dye images such as solutions of tannic acid, acondensation product of naphthalene sulfonic acid and formaldehyde, andpolyvinyl pyrrolidinone. An exceptionally useful synergistic compositionis a solution of polyvinyl alcohol containing a saccharide such asmannitol, levulose, arabinose, maltose, mannose, etc., neither thepolyvinyl alcohol nor the saccharide being effective per se to stabilizethe dye developer images.

It may be desirable to use a silver halide solvent in the process. Theuse of silver halide solvent is not to be confused with the use ofsilver halide solvent in the Wellknown silver halide diffusion transferprocesses, since in the present processes such small amounts of silverhalide solvent are used that virtually no silver halide is transferredto the receiving sheet during the transfer of the dye developed images.The presence of the silver halide solvent appears to alter thecharacteristics of the activator in that there apparently occurs acatalyst reduction of the latent image centers of the exposed areas ofthe negative element. The activator solutions which appear to have somesolvent action on the silver halide tend, especially in the presence ofthe onium compound, to produce more effective development of the exposedsilver halide grains. Also, the desired results are not obtained by useof silver halide solvent alone, in absence of either the onium compoundor the hydroquinone derivative. Useful results are obtained using fromabout 0.5 to 2 percent by Weight of silver halide solvent in thealkaline processing solution. The amount used in the receiving sheetwill vary depending in part upon the rate of diffusion of the silverhalide solvent from the sheet into the alkaline processing solution.Silver halide solvents are those commonly used in the art and having nodeleterious efi'ect on the process and include sodium, potassium andammonium thiosulfates and thiocyanates. The silver halide solvent can bepresent in the alkaline processing solution or in the receiving sheet,the hydroquinone derivative for most purposes being present in thesensitive element and less desirably in the alkaline processing solutionand the receiving sheet, and the onium compound being present in thealkaline processing solution or the receiving sheet or both but lessdesirably in the sensitive element. When both the silver halide solventand the hydroquinone derivatives are present, a substantial decrease incolor contamination and minimum density of the prints is observed. Whenthe silver halide solvent and the onium compounds are present, a similardecrease in color contamination and minimum density is obtained as wellas an appreciable decrease in color drop-01f especially when the silverhalide solvent, the hydroquinone derivative and the onium compound areall present. In addition, a substantial improvement in effective speedof the sensitive element is obtained which may have been produced by (1)a latensifying action of the silver halide solvent-containing activatorresulting in increased developer activity producing development ofgrains which may have received somewhat too little exposure to developin normal activators or by (2) physical development or intensificationoccurring simultaneously with normal development.

The invention contemplates sensitive elements wherein the emulsionlayers, contiguous hydroquinone derivatives and dye developer layers areintegral with the support e.g. coated on a support capable of receivingthe dye developed images and containing one of the developmentarrestors, the support being of a nature such that it can be strippedaway from the sensitive layers or a stripping layer may be providedbetween the reception layer and the other layers to facilitate thestripping operation. The alkaline fluid can thus be supplied asdescribed above or in case the alkali is contained in one of the layersand fluid may merely be water supplied to release the alkali.

The silver halide emulsions of the sensitive elements of the inventioninclude well-known silver halides and mixtures thereof, for example,silver bromide, silver bromoiodide or silver chlorobrimide emulsions.

The following examples will serve to illustrate the invention.

EXAMPLE l.USE OF DEVELOPMENT ARRESTOR IN RECEIVING SHEET AND ALKALINEACTI- VATOR SOLUTION A sensitive element having the structure shown inStage 1 of FIG. 1 was prepared by coating a subbed film support 10 withsuitable hardened gelatin layers as follows:

Layer 11 An aqueous gelatin solution containing the cyan dye developer(Compound I above) dissolved in a mixture of N-n-butylacetanilide,4-methy1 cyclohexanone and dispersing agent Alkanol B, and the mixturepassed through a colloid mill several times, coated and dried so as tovolatilize the 4-methyl cyclohexanone.

Layers 14, 15 and 16 Gelatino silver bromoiodide emulsion layerssensitized, respectively, to the red, green and blue regions of thespectrum.

Layers 17 and 18 Gelatin interlayers.

Layer 12 An aqueous gelatin solution containing the magenta dyedeveloper (Compound II above) dissolved in a mixture of cyclohexanone,N-n-butylacetanilide and Alkanol B, and the mixture passedthrough acolloid mill several times, coated and dried to volatilize thecyclohexanone.

Layer 13 An aqueous gelatin solution containing the yellow dye developer(Compound III above) dissolved in a mixture of ditetrahydrofurfuryladipate, ethylene glycol monobenzyl ether, and Alkanol B, and themixture passed through a colloid mill several times, the resultingdispersion chilled to set it, washed to remove ethylene glycolrinonobenzyl ether followed by coating upon layer 18 and rymg.

Alkanol B aqueous solution) ml 2 136 1 Heat at 70 C. to dissolve then0001 to 40 C. 2 Heat to 40 C.

Part A was slowly added to Part B with the aid of mechanical agitation.The solution obtained was then passed through a Manton-Gaulin laboratorycolloid mill five times. The colloid mill was then rinsed and thedispersion was adjusted to a weight of 3775 g., chill set and stored ina refrigerator.

The coating composition for layer 19 was prepared as follows:

Part I:

Dispersion D-1 g 1 3775 Water ml 1 2225 Part II:

% gelatin solution g 3180 Water ml 2 12,000 Mucochloric acid (2.7%aqueous solution) ml 2 515 1 Heat to 40 C. 2 Heat to 40 (3., adjust pHto 5.5.

Parts I and II were then combined and diluted with water to 22,700 ml.This solution was coated as layer 19 of FIG. I to yield a coverage ofapproximately 120 mg. of gelatin per sq. ft. and 40 mg. per sq. ft. of4-methylphenylhydroquinone identified hereinafter as MPHQ.

Samples of the resultant film each designated as 756 were exposed undera step table through red, green and blue filters and each wetted withthe Activators II, IX, X and XI (described below) in contact withReceiving Sheets A or C (below). After about two minutes the receivingsheets were removed and the D and D values of the prints were recordedusing red, green and blue filters in the usual manner. These data aretabulated in Table I below as Tests 1-6. By comparing Tests 1 and 2 itcan be seen that when the development arrestor Compound IX (cpd IX) wasin the receiving sheet appreciably higher D was obtained. Also, theaddition of IX to the activator (Tests 5 and 6) did not improve Dcompared to use of IX in the Receiving Sheet A (Test 3).

Moreover, use of appreciable amounts of IX in the Activator (Test 6)prevented development of the outer emulsion layer 16 to the extent thathigh yellow minimum density (1.23) was obtained in the print. Moreover.when the Activator XI contained neither development arrestor norantifoggant (Test '2) low D was obtained due to an overall fog levelcompared to use of Activator II containing antifoggant (Test 4).

COMPOUND I: 4'-methylphenylhydroquinone COMPOUND IX:1-phenyl-5-mercaptotetrazole COMPOUND X: Z-mercaptobenzothiazoleACTIVATOR I: 3.5% hydroxyethylcellulose (Hercules type 250, highviscosity); 4.5% NaOH; 2.0% benzotriazole (NF-1) (1895-141-1) ACTIVATORII: Activator I 2.0% 1-phenethyl-2- picolinium bromide (Q l)(1895-144-2, 1895-147-1) ACTIVATOR III: Activator 1 2%1-benzyl-2-picolinium bromide (Q-2) (1895-141-3) ACTIVATOR VII:Activator III 1.0% sodium thiosulfate (1895-141-6) ACTIVATOR IX:Activator II 0.005% l-phenyl-S- mercaptotetrazole (1895-144-2) ACTIVATORX: Activator II 0.05% l-phenyl-S-mercaptotetrazole (1895-14-3) ACTIVATORXI: 3.5% hydroxyethylcellulose (Hercules type 250, high viscosity); 4.5%NaOH; 2.0% l-phenethyl-Z-picolinium bromide (Q-l) (J895-1444) ACTIVATORXII: Activator XI 0.2% nitrobenzimidazole (NF-2) (J895-1472) ACTIVATORXIII: Activator XI .2% benzimidazole ACTIVATOR XIX: Activator XI 0.2%imidazole RECEIVING SHEET A: A white pigmented cellulose ester supportcarrying a layer containing 300 mg./ft. gelatin, 300 mg./ft.poly-4-vinylpyridine and 15 mg./ft. 1-phenyl-5-mercapotetrazole (K3 19-31-1) RECEIVING SHEET B: A white pigmented cellulose ester supportcarrying a layer containing 300 mg./ft. gelatin, 300 mg./ft.poly-4-vinylpyridine and 15 mg./ft. 1-phenyl-5-mercapotetrazole plus 100mg./ft. l-phenethyl-Z-picolinium bromide (J 895141-3) RECEIVING SHEET C:A white pigmented cellulose ester support carrying a layer containing300 mg./ft. gelatin, 300 mg./ft. poly-4-vinylpyridine (J 895-141-6)RECEIVING SHEET D: A white pigmented cellulose ester support carrying alayer containing 300 mg./ft. gelatin, 300 mg./ft. poly-4-vinylpyridineand 15 mg./ft. 2-mercaptobenzothiazole (K441-182) TABLE I Neutral ScaleTest No. Negative Activator Receiving Sheet Dmin Din Red Green Blue RedGreen Blue 756 (MPHQ) XI (Q1) A pd. IX 19 20 41 1. 58 1. 13 1. 756(MPHQ) XI (Q,1) C (Mordant only) .21 23 .37 1. 24 94 1. 27 756 (MPH II(NF- A pd. IX .19 .20 .25 1.97 1.60 1.93 756 (MPHQ) I (NF1) C (Mordantonly) .17 .20 .24 1. 52 1. 52 2.07 (MPH IX (cpd. IX) do .18 .21 .25 1.411.58 2.13 756 (MPH X (cpd. IX) .....(10 17 .40 1.23 1. 53 1.67 2.18 756(MPHQ) (NF- A (cpd. IX) 19 20 25 1. 97 1. 1. 93 756 (MPHQ) II (NF1) C(Mordant 0n1y) 17 20 24 1. 52 1. 52 2.07 339 (MPHQ) A (cpd. IX) 17 20.27 1. 82 1. 48 1. 83' 339 (MPHQ) 16 20 36 1.54 1. 35 1. 339 (MPHQ) .1621 41 1. 65 1. 40 1. .16 .21 51 1.39 1.15 1.83 .19 .20 .41 1. 58 1.13 1.55 .69 1.15 1. 72 1.61 1.91 2.11 55 69 95 1. 42 1. 81 1. 99 53 .89 2.32 1. 76 1. 97 2. 36 20 25 53 1. 68 1. 99 2. 49 55 69 95 1. 42 1. 81 1.99 32 25 26 1. 71 1. 79 2.05 20 25 53 1. 68 1. 99 2. 49 19 20 41 1.58 1. 13 1. 55 21 23 37 1. 24 94 1. 27 20 30 42 2.01 1. 99 2. 20 22 2536 1. 94 1. 93 2. 14

23 EXAMPLE 2.--THE USE OF A RECEIVING SHEET CONTAINING A DEVELOPMENTARRESTOR AND MORDANT Negative 756 was processed as in Example 1, withActivator II using Receiving Sheets A and C (Tests 7 and 8). The data ofTable I shows that Compound ]X increased D in the presence of a mordant.

EXAMPLE 3.-USE OF VARIOUS DEVELOPMENT ARRESTORS A negative prepared asin Example 1 and designated 339 was processed with Activators II, XII,XIII, XIV and XI using Receiving Sheet A, containing Compound DC, (Tests9l3). The data of the table show that the anti- 24 the resultthat thetwo development arrestors IX and X were found to give similar results ascan be seen from the data of Tests 23 and 24 and from viewing theprints.

EXAMPLE 7.COMPA-RISON OF USE OF ANTI- FOGGANTS AND DEVELOPMENT ARRESTORSIN RECEIVING SHEET Samples of a negative prepared as in Example 1 wereprocessed with Activator VII using control receiving sheets containingpo1y-4-vinylpyridine mordant and experimental sheets containing thismordant plus the compounds shown in Table II (Tests l-17). The maximumdensities of the neutral scale to red, green and blue light wererecorded and the change in maximum density foggants of Tests 9-12 allproduced beneficial results com- 15 (A D caused by the compounds isshown in Table H.

TABLE II Neutral Scale (AD-n) Test Compound Red Green Blue1-phenyl-5-mereaptotetrazole 05 07 5-myristoylthio-l-phenyltetrazole 1008 09 5-5 aeetylethylthio-l-phenyltetrazole 11 03 06 2-mereapto-5phenyl-l, 3, 4-oxad1azole 15 21 Zmereaptonaphthll, 2]oxazole 11 05 032-mercaptobenzoxazole 09 07 162-(2-d.iearbethoxy)ethylmercaptobenzoxazole 11 04 07 Potassium iodide 1219 24 Benzothizaole methiodide 32 28 Bls-(2-amino-5-iodopyridine hydroe) rc dide 09 18 21 Thiovarbiturie acid 19 08 06 Benzotriazole 15 07 15Benzothiazole metho methyl sulfate 06 03 11 Thioacetanilide 02 06 157-mercapto-1, 3, 4, G-tetrazaindene- 05 03 99 l-methyl-l, 2, 3,fi-tetrahydrol-l, 3, 5-triazine-4-thiol 1. 07 83 85 l-cyelohexyl-l, 2,3, fi-tetrahydro-l, 3, 5-triazine-4-thiol 1. 19 1. 31 1.49

pared to Test 13 where no antifoggant was in the solution.

EXAMPLE 4.EFFEOT OF HYDROQUIN ONE DERIVATIVE IN NEGATIVE Negative 371(containing MPHQ and prepared as in Example 1) and 368 prepared in thesame manner but containing no MPHQ in layer 19, were processed withActivator I and Receiving Sheets A and B with the results shown in TableI (Tests 14-17). In the presence of MPHQ an appreciable decrease in D isobtained (Tests 14 vs. 15). Moreover, the print of Test 15 showedreduced color contamination. When the quaternary salt Q-l was present,reduced color contamination, drop-01f and minimum density was obtained(Tests 14 vs. 16). When both MPHQ and Q-l were present an even greaterincrease in D and reduction in D was obtained (Test 15 vs. 17). Also theprint of Test 17 showed even less color contamination and drop-off.

EXAMPLE 5.EFFECT OF QUATERNARY SALT Negatives prepared as in Example 1(756) were processed with Activators I, II and XI using Receiving SheetsA, B and C in the combinations and with the results shown in Tests 18-22of Table I. The data show that very substantial improvement in D and Dwere obtained when the activator contained an antifoggant (NF-1) and theReceiving Sheet contained a development arrestor (DO i.e. Tests 19 to 22vs. 18. Less color drop-off and color contamination also showed in theprints. However, useful results were observed from a system where theactivator did not contain antifoggant while the receiving sheetcontained development arrestor and quaternary compound.

EXAMPLE 6.USE OF Z-MERCAPTOBENZO- THIAZOLE A negative 646 prepared as inExample 1 was processed with Activator HI using Receiving Sheets A and Dwith The data of Tests 1-10 clearly show the substantial improvement inD obtained by use of the development arrestors in the receiving sheets.Tests 11-17 show that the antifoggant compounds either reduced or onlyslightly improved D accompanied by other disadvantages. Thus,benzothiazole reduces D compared to increasing D when it is present inthe activator (Tests 1, 2, Table I). Thiobarbituric acid in addition toreducing D (Table II, Test 11) produced overall yellow strain on theprint. Thioacetanilide slightly increased the D but disadvantageouslyincreased minimum density of the prints. The compounds of Tests 15, 16and 17 reduced D very greatly as can be seen.

The unique results obtained with the heterocyclic quaternary ammoniumcompound forming methylene bases may be due to their reaction with twomoles of a quinone (obtained by oxidation of a dye developer or otherhydroquinone derivative) to form an addition product of the quinone andthe methylene base and regenerate a hydroquinone, as shown by James,Snell and Weissberger J.A.C.S. 60 2084 (1938).

The emulsion addenda described in the Whitmore et al. US. Patentapplication Serial No. 734,141, filed May 9, 1958, now abandoned, andFrench Patent 1,205,755, August 17, 1959, including the noble metalsalts, stannous salts, polyamides, optical sensitizing dyes, mercury andazaindene stabilizing compounds, quaternary ammonium salt andpolyethylene glycol speed-increasing compounds, plasticizers, hardeners,coating aids in colloid vehicles disclosed therein may be usedadvantageously in the silver halide emulsion layers and adjacent layersof the sensitive elements of the present invention.

What we claim is:

1. A multicolor diffusion transfer process which comprises exposing to asubject a sensitive element including a plurality of light-sensitivesilver halide emulsion layers sensitive to different regions of thespectrum, dye developers being contiguous to the silver halide of eachemulsion layer, said dye developer being a compound which is both asilver halide developing agent and a dye, applying an alkaline solutionto the emulsion layers while they are in superposed contact with areception layer containing a silver halide development arrestordiffusible in the alkaline solution selected from the group consistingof (a) amercaptoazole,

(b) an azole that hydrolyzes in alkaline solution to form amercaptoazole,

(c) an iodide, and

(d) an iodine-containing compound that releases an iodide in alkalinesolution,

thereby developing the silver halide and rendering the dye developersnon-diffusing in the region of development, the development arrestordifiusing to the emulsion layers and stopping further development,allowing the dye developers in the undeveloped regions to transferimagewise by diffusion and in register to the reception layer, andremoving the reception layer to obtain a multicolor image thereoncomposed of the dye developers.

2. The process of claim 1 wherein the development arrestor is a memberof the class consisting of iodides diffusible in the alkaline solutionand compounds releasing in alkaline solution iodides difi'usible in thealkaline solution.

3. The process of claim 1 wherein the development arrestor is a memberof the class consisting of mercapto azoles ditfusible in alkalinesolution and azoles hydrolyzing in the alkaline solution to yieldmercaptoazoles diffusible in alkaline solution.

4. The process of claim 1 wherein the alkaline solution contains anantifoggant for silver halide.

5. The process of claim 1 wherein the sensitive element contains red,green and blue light-sensitive emulsion layers coated in order on asupport, and the dye developers are subtractively colored and present incontiguous layers underlying the emulsion layers.

6. The process of claim 1 wherein a substantially colorless andsubstantially water-insoluble hydroquinone soluble and diflFusible inthe alkaline solution is present in a layer of the sensitive element.

7. A multicolor diifusion transfer process as described in claim 1wherein the development arrestor is selected from the group consistingof 1) 1-phenyl-5-mercapto-1,2,3,4-tetrazole,

(2) S-myristoylthio-l-phenyl-l,2,3,4-tetrazole,

(3) S-B-acetylethylthio- 1-phenyl-1,2,3 ,4,-tetrazole,

(4) 3-mercapto-5-pheny1-1,3,4-oxadiazole,

(5) 2-mercaptonaphth( 1,2,) oxazole,

(6) Z-mercaptobenzoxazole,

(7) 2-mercaptobenzothiazole,

(8) 2-(2'-dicarbethoxy)ethylmercaptobenzoxazole,

(9) Potassium iodide,

(10) Benzothiazolium methiodide, and

( 1 1) Bis(2-amino-5-iodopyridine hydroiodide) mercuric iodide.

8. The process of claim 1 wherein the alkaline solution contains aquaternary ammonium compound diifusible in the alkaline solution.

9. In the processing of an exposed photographic element comprising asupport, superposed red, green and blue light-sensitive silver halideemulsion layers, and a dye developer which is both a silver halidedeveloping agent and a dye contiguous to the silver halide of each ofsaid silver halide emulsion layers, said processing being effected bytreating said photographic element with an aqueous alkaline solution,developing latent images in the regions of exposure of said silverhalide emulsion layers and thereby immobilizing dye developers in saidregions of exposure, dye developers in undeveloped regions diffusingimagewise to the surface of said photographic element, and transferringthe resulting difiused images from said undeveloped regions in registerto a dye developer receiving sheet superposed on said photographicelement, the improvement which comprises utilizing 1-phenyl-5-mercapto-,2,3,4-tetrazole as a silver halide developmentarrestor in said receiving sheet.

References Cited by the Examiner UNITED STATES PATENTS 2,334,864 l1/1943Carroll et al 96109 X 2,636,821 4/1953 Sargent 9622 2,725,290 11/1955Smith 9622 2,784,090 3/1957 Carroll 96107 2,886,437 5/1959 Piper 96662,983,606 5/1961 Rogers 9629 3,017,270 1/ 1962 Tregillus et a1 96293,020,155 2/1962 Yackel et al 9629 NORMAN G. TORCHIN, Primary Examiner.

HAROLD N. BURSTEIN, Examiner.

B. E. EDELSTEIN, G. H. BJORGE, J. T. BROWN,

Assistant Examiners.

1. A MULTICOLOR DIFFUSION TRANSFER PROCESS WHICH COMPRISES EXPOSING TO ASUBJECT A SENSITIVE ELEMENT INCLUDING A PLURALITY OF LIGHT-SENSITIVESILVER HALIDE EMULSION LAYERS SENSITIVE TO DIFFERENT REGIONS OF THESPECTRUM, DYE DEVELOPERS BEING CONTIGUOUS TO THE SILVER HALIDE OF EACHEMULSION LAYER, SAID DYE DEVELOPER BEING A COMPOUND WHICH IS BOTH ASILVER HALIDE DEVELOPING AGENT AND A DYE. APPLYING AN ALKALINE SOLUTIONTO THE EMULSION LAYERS WHILE THEY ARE IN SUPERPOSED CONTACT WITH ARECEPTION LAYER CONTAINING A SILVER HALIDE DEVELOPMENT ARRETORDIFFUSIBLE IN THE ALKALINE SOLUTION SELECTED FROM THE GROUP CONSISTINGOF (A) A MERCAPTOAZOLE, (B) AN AZOLE THAT HYDROLYZES IN ALKALINESOLUTION TO FROM A MERCAPTOAZOLE, (C) AN IODIDE, AND (D) ANIODINE-CONTAINING COMPOUND THAT RELEASES AN IODIDE IN ALKALINE SOLUTION,THEREBY DEVELOPING THE SILVER HALIDE AND RENDERING THE DYE DEVELOPERSNON-DIFFUSING IN THE REGION OF DEVELOPMENT, THE DEVELOPMENT ARRESTORDIFFUSING TO THE EMULSION LAYERS AND STOPPING FURTHER DEVELOPMENT,ALLOWING THE DYE DEVELOPERS IN THE UNDEVELOPED REGIONS TO TRANSFERIMAGEWISE BY DIFFUSION AND IN REGISTER TO THE RECEPTION LAYER, ANDREMOVING THE RECEPTION LAYER TO OBTAIN A MULTICOLOR IMAGE THEREONCOMPOSED OF THE DYE DEVELOPERS.